The objective is to determine whether the enhanced rate of glucose metabolism exhibited by virus transformed mammalian cells in culture is primarily due to an alteration of the regulation of glucose transport or to an alteration of the regulation of glycolysis. To determine with certainty whether the increased rate of glucose utilization occasioned by viral transformation is in fact due to increased transport, initial rates of the entry of the glucose analog 2-deoxy-D-glucose into free and phosphorylated intracellular pools will be measured. This is to determine whether transport of the sugar or its subsequent phosphorylation is the rate limiting event in its uptake. Further, glucose transport will be studied under conditions where phosphorylation does not take place. This will be approached through the use of isolated membrane vesicles, the use of glucose analogs that are not phosphorylated, such as 6-deoxy-D-glucose, and through an attempt to isolate hexokinase-deficient mutants. To determine whether observed differences are due to normal variations in growth rate or specifically to viral transformation, studies will be made with actively growing untransformed cells (BALB/C 3T3) at low cell densities, untransformed cells that have reached population density inhibition, a spontaneously transformed cell line (3T6) that carries no known virus, cells transformed with SV40 virus, and a cell line transformed with a temperature sensitive SV40 mutant that shows transformed characteristics only at the permissive temperature. Sugar transport rate will be related to cellular growth rate in an effort to determine the physiological significance of altered rates of transport.